ON UNDERGROUND TEMPERATURE. 129 



of the new pattern iloscribed in the Report (the upright I^egrctti pattern), 

 und one of these instruments was accordingly sent. 



Dr. Wild, of the Central Observatory, St. Petersburg, wrote in January, 

 requesting that two thermometers for observations in bores might be ordered 

 in his name. At this time the Secretary was in correspondence with Sir 

 Wm. Thomson, who entertained doubts as to the successful working of the 

 new thermometer, and expressed a preference for the Phillips pattern 

 (which has been described in preceding Eeports) and the Casella-Miller 

 pattern (a modified Six), which has been extensively used for deep-sea 

 temperatures. Thermometers of these two patterns were accordingly ordered 

 and despatched to Dr. Wild. 



A letter was received from Prof. Henry, of the Smithsonian Institution, 

 Washington, in April, stating that the Chief Engineer of the Hoosac Tunnel 

 had promised to have observations of temperature taken in the tunnel, if 

 thermometers were sent. Its total length will be 4| miles, about two 

 thirds of which has been penetrated, by working from both ends and from 

 a central shaft 1028 feet deep. The mountain has two ridges, under 

 which the tunnel passes, and their heights above it are respectively 1720 

 and 1420 feet. Four thermometers have been sent, viz. two large mini- 

 mum Rutherfords, for observations in the tunnel, and two upright Negrettis, 

 for observations in the shaft. 



The Council of the School of Mines at Ballar-at, Australia, have, in com- 

 pliance with a request addressed to one of their number by our observer, 

 Mr. David Burns, C.E., consented to take charge of some thermometers, and to 

 furnish observations from the bores and shafts iu that important gold-mining 

 district. Most of the principal mining manager's are connected with the 

 school. Four thermometers have accordingly been sent, viz. two upright 

 Ifegrettis for observptions in bores, and two simple mercurial thermometers, 

 of large size, for obLcrvations during the sinking of shafts. 



Some exceedingly deep Artesian borings have been undertaken in Franco 

 in recent years ; and the President of the Geological Society, Mr. Prest- 

 "wich (who has allowed his name to be added to your Committee), has fur- 

 nished your Secretary with introductions which wiU probably lead to the 

 obtaining of very numerous and valuable observations from these wells. 



The largest of them all is one which is now sinking for the municipality 

 of Paris, at La Cbapelle, St. Denis, a northern suburb of Paris, and has 

 ali-eady obtained a depth considerably exceeding that of the Puits de Gre- 

 neUe. It is expected that its final depth will be about 2300 feet. Appli- 

 cation was made by the Secretary to the eminent firm of well-borers, Messrs. 

 Mauget, Lippmann, anu Co., who are sinking the well, and these gentlemen 

 at once, in the most obliging manner, consented to take observations of tem- 

 perature in i*-. An upri jht Negretti thermometer was accordingly furnished ; 

 and about the 20th of June your Secietary had the pleasure of receiving from 

 them two complete sets of observations taken on the 14th, 15th, 17th, and 

 18th of that month with their own hands, at every 100th metre of depth, 

 and also at the bottom of the well, 660 metres deep. 



The observations are given in the subjoined Table, iu which the third 

 column shows the time that the thei'mometer was allowed to remain at the 

 depth specified before hauling up and reading. The temperature at which 

 the thermometer was set before letting jt down is also given in Messrs. 

 Mauget and Lippmanu's report, but is not here inserted. 



